Japan Volcano Alerts MCP

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It usefully discloses that the result may be large and that PRO access applies, but says nothing about rate limits, pagination, ordering, or how large results should be handled.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short, front-loaded fragments with no wasted text. The size warning is placed immediately where the agent will see it.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter read tool this covers the core: what is returned (JSON list), that it may be large, and that PRO access is involved. It still omits how to handle large results and when to choose it over the sibling tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the sole access_token parameter is already fully documented in the schema. The description only hints at PRO subscription gating and adds no parameter syntax or format detail beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific resource and scope: the full JMA volcano warning JSON list. It implies 'list/retrieve' rather than 'search' or 'latest', but does not explicitly name or differentiate from the siblings latest_volcano and volcano_search.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit guidance on when to use this tool versus latest_volcano or volcano_search. 'PRO' signals subscriber eligibility, not task-selection guidance, and there are no exclusions or alternatives mentioned.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden; it usefully discloses the hard result cap (newest 5) and that the call is free, which are real behavioral facts beyond the schema. It says nothing about data freshness, update cadence, whether results can be empty, or that the operation is read-only (though that is inferable).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences with no waste, and the most decision-relevant fact (FREE) is front-loaded. The result cap follows immediately.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter fetch of the latest entries, the description gives source, scope, and cardinality, which is nearly everything needed to invoke it. Without an output schema it could mention the shape of a warning entry, but the gap is minor for a tool this simple.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there are no parameter semantics to explain; the baseline of 4 applies. Nothing in the description misrepresents the input surface.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb implied by 'Latest ... entries' and a specific resource, JMA volcano warnings, with scope 'newest 5'. It is distinguishable from volcano_search (search) and all_warnings (all warning types), though it never names those siblings explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by 'Latest' and the 5-entry cap, but there is no explicit when-to-use guidance and no mention of when volcano_search or all_warnings would be preferable. An agent can infer this is the quick recent-alerts fetch, but the description does not route it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description must carry behavioral disclosure. It only says "PRO" and search-by-keyword; it does not describe read-only behavior, authentication expectations beyond the schema token field, rate limits, or result behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The definition is short and front-loaded, with no wasted sentences. The only weakness is that "PRO." is ambiguous and not integrated into the main sentence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple, and the description gives enough to understand the core search behavior. However, with no annotations and no output schema, it should say more about access requirements or what kind of bulletin results are returned.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 50%. The description usefully explains that keyword means volcano name or level text, adding meaning beyond the schema, while access_token is documented in the schema itself.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: "Search volcano bulletins by keyword." It also clarifies that the keyword targets volcano name or level text, distinguishing it from a generic search, though it does not name the sibling tools explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It implies keyword-based use but gives no explicit guidance on when to choose this over siblings like latest_volcano or all_warnings. There are no exclusions, prerequisites, or alternative-routing instructions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.